A consumption meter may be used for measuring utility usage in connection with supply of the utility, e.g. of water, gas, heating, or cooling, such as distributed water supply, distributed gas supply, district heating, or district cooling and may in turn be used in connection with charging of the consumed quantity of the utility.
Such consumption meters may operate by way of wireless data transmission, such as by way of wireless radio frequency data transmission.
Wireless data transmission from consumption meters placed at the premises of a consumer offers a number of advantages: The need for on-site reading is eliminated, which otherwise may involve labour intensive and time consuming and in turn costly processes. Further, wireless transmission offers advantages in terms of the option of more frequent and close monitoring and control of utility consumption, as well as the elimination of human errors related to manual reading procedures.
With wireless transmission, however, power management in terms of management of the power consumption of the transmission system of the consumption meter is essential. In particular with consumption meters with no external power supply, such as water, heating and cooling meters, which are traditionally battery powered, the lifetime of consumption meters is likely defined by the lifetime of the battery, and transmission power should preferably be closely controlled and minimized.
On the other hand, in particular with below-ground applications like pit and basement applications, the demands on the transmission system are high. With such applications, due to interference, reflection and absorption, signal transmission is often heavily attenuated, and it is essential that the consumption meter provides optimal transmission efficiency relative to its power consumption.
One approach hereto is to arrange a transmission system with the lid of a pit to minimize signal attenuation. Thus as disclosed with U.S. Pat. Nos. 5,298,894 and 5,825,303 to Badger Meter, Inc. a transmitter system in terms of a transponder and an antenna assembly is arranged at a pit lid, for converting data signals received from a consumption meter in the pit to radio frequency signals for transmission via the antenna.
Another approach relates to more modern consumption meters which comprise transmitters integrated with the body of the consumption meter. Although such integrated transmitters offer elegant solutions, their transmission power may be limited. Thus U.S. Pat. No. 6,262,685 to Itron, Inc. discloses a consumption meter in which an integrated transmitter is coupled to an external radiator for wireless communication therefrom to obtain an improved transmission over transmission directly from the integrated transmitter.
Also U.S. Pat. No. 6,369,769 to Innovatec Communications, LLC relates to a consumption meter with an integrated transmitter. The consumption meter has an antenna coupled thereto by means of a cable, the antenna being arranged in an antenna housing with a pit lid. The coupling from the consumption meter to the cable is capacitive or inductive by means of an antenna receptor arranged in a separate housing at the exterior of the consumption meter.
Similar approach is applied with German Patent Application DE 10 2007 008 469 A1 to Techem Energy Services GmbH, wherein a communication unit for transmission of measurement data from a utility meter comprises a primary antenna arranged with the communication unit and a secondary antenna arranged at the exterior of the housing of the communication unit, and being coupled to the primary antenna by means of near-field coupling.
Still, however, there is a need for data transmission systems for consumption meters, in particular for consumption meters for below-ground applications, with high transmission efficiency and simple mechanical handling.